This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Extracorporeal membrane oxygenation (ECMO) is an accepted therapy for newborns with life-threatening conditions such as diaphragmatic hernia, pulmonary hypertension of the newborn and severe congenital heart disease. These patients are at risk of compromised cerebral perfusion and/or of developing renal failure during ECMO. The efficacy of tissue perfusion in these patients is estimated by a variety of indirect means tissue lactate content, acidosis, blood gas parameters, etc. The primary purpose of this observational study is to assess bilateral cerebral oxygenation when one cerebral hemisphere is potentially compromised, i.e. unilateral carotid ligation or large venous cannula. Furthermore, we hope to relate oxygen saturation to short and long term neurodevelopmental outcomes and to relate renal oxygen saturation to incidence of ECMO related renal failure. Near-infrared spectroscopy (NIRS) is a non-invasive technique that can be used to compute the oxygen saturation for blood in certain tissues. The regional cerebral oxygen saturation index (rSO2i) represents the weighted average of the oxygen saturation of the arteries, venules, and capillaries in certain regions of the brain. We will use this technology to monitor the cerebral blood oxygen saturation of our patients from birth until they go on ECMO, while they are on ECMO, during any surgical repair of defects (whether on ECMO at the time or not), and while the patients are being weaned from ECMO. NIRS data will also be collected from a control group of ECMO candidate neonates that are not placed on ECMO. After the patients have recovered, are off of mechanical ventilation, and are progressing well, a brain MRI is typically performed prior to discharge. The findings of these MRIs as well as the findings of neurological and neurodevelopmental examinations made at six months and one year of age will be analyzed.